蟹类主要过敏原及其消减技术研究进展

蟹是引起食源性过敏的主要食品之一,蟹类过敏原是引起蟹过敏的根源。近年来,过敏原性质的研究及分离纯化技术备受关注,已发现蟹的主要过敏原包括原肌球蛋白、精氨酸激酶、血蓝蛋白等。利用食品加工技术降低蟹致敏性的研究也日益增多,以热加工法、辐射技术、酶处理法和超高压法等为代表的蟹致敏活性消减技术取得了新进展。本文就蟹类主要过敏原的种类、致敏蛋白的制备、蟹与其他甲壳类的交叉过敏性以及蟹类过敏原消减方法等进行综述,以期为蟹过敏的诊断预防和低致敏产品开发提供参考。     

食品中常见过敏原及检测技术研究进展

近年来，食物过敏发生率呈现上升趋势，由食物过敏引发的食品安全问题引起广泛关注。目前对于食物过敏尚无有效治疗手段，避免摄入含过敏原食物是最有效的预防方式。因此，过敏原检测与标识对过敏人群具有重要的警示意义。本文介绍了8 类常见致敏食品中主要过敏原的结构与致敏特点，综述了现阶段用于过敏原检测的主要技术，包括基于蛋白水平的免疫学检测技术、基因水平的分子生物学检测技术以及质谱技术，分析了各方法的优势与局限性，并对过敏原检测技术的发展方向进行了展望。     

食品中过敏原及其检测方法的研究进展

近年来食物过敏作为食品安全的热点问题在全球引起了广泛关注。目前食物过敏仍无有效的根治方法,严格避免摄入致敏食品仍是过敏性疾病防治的最有效方式。因此,食品中过敏原的识别鉴定、性质分析及检测方法的研究至关重要。本文针对八大类过敏食物,从分子结构、免疫学特性等方面介绍了常见食物过敏原的研究进展;归纳了现阶段用于食品中过敏原分析的常规检测方法,以及在此基础上发展而来的新兴检测丰富,并比较分析了不同检测技术方法的优缺点。相比于植物源性过敏原,动物源性过敏原的相关研究有待深入,尤其是蛋白家族的确定及空间结构解析等是未来动物源性过敏原研究的重要方向;目前食品中常见过敏原的常规检测方法及新兴检测方法依然存在检测效率和准确性不高、成本昂贵等局限性,建立高效、准确、低成本的过敏原检测方法仍是该研究领域发展的重要趋势。     

芝麻过敏原及其致敏性消减技术研究进展

芝麻是新的“8大类”过敏食物之一,芝麻过敏反应由于其潜在危害性及其日益上升的发病率而越来越引起全世界的普遍重视,因此研究芝麻致敏性消减技术在保障食品安全方面具有重要意义。概述了芝麻主要过敏原(Ses i 1～Ses i 7)的结构和免疫特性,及其致敏性消减技术原理和研究进展;已报道的芝麻过敏原有7种,属于2S白蛋白、7S类豌豆球蛋白、油质蛋白和11S球蛋白,其中11S球蛋白和2S白蛋白是主要的过敏原蛋白。利用热加工技术消减芝麻致敏性,主要通过煮沸、微波、烘焙等工艺引起过敏原的解聚、变性进而破坏致敏表位;高压、辐照、发酵、酶解等非热加工技术通过氢键、疏水键等化学键的变化、多肽链的断裂引起蛋白结构变化,从而掩盖或直接降解致敏表位。另外,结合其他食品过敏原,对芝麻过敏原的潜在消减技术,包括脉冲电场、冷等离子体、超声波、脉冲光、糖基化改性和复合加工技术等进行了阐述分析。未来需要进一步研究芝麻不同过敏原的致敏表位、不同加工工艺对过敏原结构及致敏性影响、开展血清学、细胞和动物模型等致敏性评价等,以明确芝麻致敏性消减的主要机制,以期为生产低敏或脱敏芝麻产品奠定理论依据与科学指导。     

桃过敏原的种类、制备、鉴定及检测技术研究进展

作为日常食用的植物源食品,水果可为人体提供糖类、维生素、矿物质等多种营养物质,从而调节机体的多项生理功能。然而,水果中的致敏成分可诱发过敏反应,由此引发的食品安全问题也越来越引起关注。桃是一种最常见的过敏水果,可引起轻微过敏症状和严重过敏反应甚至过敏性休克。文章综述桃过敏原的种类、亚类及其生物特性,阐述不同亚类桃过敏原在品种或地区的差异性,总结桃过敏原的分离制备方法和分子鉴定技术,并从过敏原基因检测、免疫检测技术和仪器检测技术3个方面对桃过敏原检测技术进行概括,以期为桃过敏原的致敏机制、消减技术和食品加工的安全控制提供研究基础。     

基于总过敏原家族的食物过敏原家族分类

目的 根据过敏原数据库对食品过敏原进行分类。方法 从致敏性蛋白结构数据库SDAP(Structural Database of Allergenic Proteins)中获得已知食品过敏原列表, 将这些食品过敏原在AllFam数据库中进行整理分类。结果 根据分类结果, 得到涵盖食品过敏原数量最多的五个家族分别是Prolamin superfamily、Bet v 1-related protein、EF hand domain、Cupin superfamily和Profilin, 他们包含了大约60%的食物过敏原。研究还发现3个交叉过敏原家族, 分别是Serpin serine protease inhibitor、Thioredoxin和Triosephosphate isomerase。结论 这个分类包含植物性食品过敏原和动物性食品过敏原两大类, 并使用了过敏原家族数据库AllFam, 为科学研究食品过敏原的结构和功能及动物致敏试验、临床致敏试验的设计和开展提供了客观依据。     

虾类过敏原及消减方法研究进展

虾及其制品味道鲜美,营养丰富,但却具有较高的致敏性。本文综述国内外有关虾类主要过敏原——原肌球蛋白的结构、表位预测与定位、变态反应原性检测及脱敏方法等方面的研究进展,为进一步研究虾类过敏原及其消减技术提供一定的参考。     

体外消化模型评估食物过敏原致敏性研究进展

食物过敏受到了人们的广泛关注，检测和评价食物过敏原的潜在致敏性日益受到重视。体外胃肠道消化实验是食物过敏原潜在致敏性评价体系的重要环节之一。该文系统介绍体外胃肠道消化模型的种类及其应用，并综述体外消化模型与体内消化模型相比的优缺点，最后对食物过敏原消化稳定性与潜在致敏性的关系进行探讨，以期为食物过敏原潜在致敏性评价研究中体外模拟消化方法的应用及消化结果分析提供参考。     

食物过敏原及检测技术的研究进展

食物过敏是当前食品安全领域较为突出的问题,综述食品过敏原、过敏的免疫学发生机制及检测技术等方面的研究现状及发展展望,涉及致敏的食物种类及相应过敏原,过敏的免疫学分子发生机理,并对食物过敏原现存的检测技术做了相关的介绍。     

食品致敏性评价的动物和细胞模型研究进展

食品过敏原致敏性的评价方法多种多样,而动物模型和细胞模型的致敏性评价是常用的方法之一。小鼠模型拥有繁殖周期短和遗传基因可操作性等优点,但却有着遗传背景差异性、伦理上等局限性;而体外培养细胞模型正好弥补了动物模型上的不足从而反映出机体中过敏反应从大体到细节上的变化。虽然目前有许多评价食品致敏性的方法,如常用的胃肠道消化实验法和热稳定性试验法,然而这些方法都存在着一定的局限性。本综述概括了动物和细胞模型在目前研究中的优缺点以及与其他实验方法的相互关系,客观分析其在评估食品过敏原的致敏性中的作用。     

Food Allergens: Is There a Correlation between Stability to Digestion and Allergenicity?

Food allergy is a major health problem in the Western countries, affecting 3–8% of the population. It has not yet been established what makes a dietary protein a food allergen. Several characteristics have been proposed to be shared by food allergens. One of these is resistance to digestion. This paper reviews data from digestibility studies on purified food allergens and evaluates the predictive value of digestibility tests on the allergenic potential. We point out that food allergens do not necessarily resist digestion. We discuss how the choice of in vitro digestibility assay condition and the method used for detection of residual intact protein as well as fragments hereof may greatly influence the outcome as well as the interpretation of results. The finding that digests from food allergens may retain allergenicity, stresses the importance of using immunological assays for evaluating the allergenic potential of food allergen digestion products. Studies assessing the allergenicity of digestion products, by either IgE-binding, elicitation or sensitizing capacity, shows that digestion may abolish, decrease, have no effect, or even increase the allergenicity of food allergens. Therefore, the predictive value of the pepsin resistance test for assessing the allergenic potential of novel proteins can be questioned.     

Development of a Biological Assay to Determine the Allergenic Potential of Foods

Food allergies represent a risk for many people in industrialized countries. Unrecognizable allergenic proteins of foodstuffs may be present as ingredients that are not labeled or as unknown cross-contamination. Such hidden allergens can cause severe reactions in allergics, even at minute quantities, sometimes with fatal outcome. For the verification of the presence of allergenic food constituents, analytical methods such as ELISA and PCR have been developed. However, these tests cannot measure allergenic potential. For this reason, a test system that measures the biological activity of allergens has been developed. It is based on the cellular mechanisms of the type I allergy. Rat basophilic leukemia cells (RBL-2H3) were transfected with the genes of the human high affinity receptor for IgE. The resulting cell line expressed the human receptor α-chain and could bind allergenspecific IgE from allergic subjects, in contrast to the parent cell line. After cross-linking of receptor-bound, allergen-specific human IgE by allergens, the cells released measurable inflammatory mediators. These cells were used for the analysis of a variety of allergen extracts, including extracts prepared from foods containing allergenic hazelnut and peanut. The comparative validation with existing ELISA and PCR for hazelnut and peanut demonstrated similar sensitivity and specificity. The established cell line will be a novel tool in the detection of allergens in complex mixtures, especially to address the issue of their allergenic potential, which cannot be accomplished by classical analytical methods. This will add valuable information about the allergenic potential of food constituents to the risk assessment of foods.     

Cleaning and other control and validation strategies to prevent allergen cross-contact in food-processing operations

Food allergies affect an estimated 10 to 12 million people in the United States. Some of these individuals can develop life-threatening allergic reactions when exposed to allergenic proteins. At present, the only successful method to manage food allergies is to avoid foods containing allergens. Consumers with food allergies rely on food labels to disclose the presence of allergenic ingredients. However, undeclared allergens can be inadvertently introduced into a food via cross-contact during manufacturing. Although allergen removal through cleaning of shared equipment or processing lines has been identified as one of the critical points for effective allergen control, there is little published information on the effectiveness of cleaning procedures for removing allergenic materials from processing equipment. There also is no consensus on how to validate or verify the efficacy of cleaning procedures. The objectives of this review were (i) to study the incidence and cause of allergen cross-contact, (ii) to assess the science upon which the cleaning of food contact surfaces is based, (iii) to identify best practices for cleaning allergenic foods from food contact surfaces in wet and dry manufacturing environments, and (iv) to present best practices for validating and verifying the efficacy of allergen cleaning protocols.     

模拟消化方法在食物过敏原潜在致敏性评价中的应用进展

食物过敏已成为全球范围内日益严重的食品安全问题。对食物过敏原的潜在致敏性进行评价有助于更好地了解食物过敏原自身特性及其对过敏人群免疫系统的影响。模拟消化实验是食物过敏原潜在致敏性评价的有力手段。食物过敏原蛋白的消化稳定性为其潜在致敏性评价结果提供了重要参考依据,但并非所有食物过敏原均具有较强的消化稳定性。食物过敏原的潜在致敏性一方面取决于过敏原蛋白在通过消化道时的消化稳定性,另一方面取决于消化产物中具有免疫刺激能力的过敏原表位的丰度。不同模拟消化方法的应用对食物过敏原的消化结果及潜在致敏性评价结果的真实性和可比性具有重要影响。本文系统地介绍了体内及体外模拟消化方法的优缺点及在食物过敏原潜在致敏性评价中的应用研究进展,并综述了食物过敏原消化稳定性与其潜在致敏性评价结果的关系。以期对食物过敏原致敏性评价体系的进一步完善和发展有所帮助。     

Effect of roasting history and buffer composition on peanut protein extraction efficiency

Peanut is a major allergenic food. Undeclared peanut (allergens) from mis-formulation or contamination during food processing pose a potential risk for sensitized individuals and must be avoided. Reliable detection and quantification methods for food allergens are necessary in order to ensure compliance with food labelling and to improve consumer protection. The extraction of proteins from allergenic foods and complex food products is an important step in any allergen detection method. In this study, the protein extraction efficiency of various buffers prepared in-house and some extraction buffers included in some commercial allergen enzyme-linked immunosorbent assay (ELISA) test kits for peanut determination in food products were tested. In addition, the effect of roasting history on the extractability of peanut protein was investigated by the biuret and the bicinchoninic acid (BCA) assays. Elevated roasting temperatures in food processing were found to have a major impact on protein extraction efficiency by reducing protein yields of oil and dry roasted peanuts by 50-75% and 75-80%, respectively, compared with the raw material. Extraction buffers operating in the higher pH range (pH 8-11) showed best yields.     

Advanced DNA- and Protein-based Methods for the Detection and Investigation of Food Allergens

Currently, food allergies are an important health concern worldwide. The presence of undeclared allergenic ingredients or the presence of traces of allergens due to contamination during food processing poses a great health risk to sensitized individuals. Therefore, reliable analytical methods are required to detect and identify allergenic ingredients in food products. The present review addresses the recent developments regarding the application of DNA- and protein-based methods for the detection of allergenic ingredients in foods. The fitness-for-purpose of reviewed methodology will be discussed, and future trends will be highlighted. Special attention will be given to the evaluation of the potential of newly developed and promising technologies that can improve the detection and identification of allergenic ingredients in foods, such as the use of biosensors and/or nanomaterials to improve detection limits, specificity, ease of use, or to reduce the time of analysis. Such rapid food allergen test methods are required to facilitate the reliable detection of allergenic ingredients by control laboratories, to give the food industry the means to easily determine whether its product has been subjected to cross-contamination and, simultaneously, to identify how and when this cross-contamination occurred.     

Considerations on Developing Criteria to Determine Whether a Food Allergen is of Public Health Importance

Food allergy is the result of a particular type of immune response against one or more food components, usually proteins. The food allergy reactions that are the focus of regulatory measures are mediated by antibodies of the IgE class. Importantly, food allergy is a two-step process. The first step, the sensitisation phase, consists of an immune response resulting in production of IgE antibodies specific for the allergen. The second step, the provocation phase, is the triggering of a symptomatic allergic reaction as a result of exposure to the allergen after sensitisation has been established. For reasons not well understood, a majority of sensitised individuals never will experience clinical reactions. Determining the number of sensitised individuals (test positives) in a population will therefore grossly overestimate the prevalence of food allergy. The term ‘allergy’ should be used only if clinical reactions occur. For triggering a food allergic reaction in a sensitised individual, only the ‘acute’ food intake and not the intake over time is of importance, and food allergy in this aspect resembles acute poisoning. Because of the cultural, agricultural, economic and nutritional importance of the foods, society accepts that a small fraction of the population develops allergies to traditional food products. Prevention of allergic reactions is then sought by means of education and by labelling of the most important allergenic foods. However, some 200 allergenic foods have been described, but only a small minority of these appears to be of importance in terms of frequency and severity of reactions triggered in the population. When it comes to management of the allergens, however, there is a lack of clear criteria at two levels: at the level of defining what documentation should be required to enter a proposed new food allergen into one of the large allergen databases, as well as at the level of determining which food allergens are of sufficient public health importance to require special regulatory attention in terms of labelling. With the aim of increasing transparency and predictability of decision-making processes and obtaining more consistency between labelling of different allergens as well as between labelling of allergens in different food regulatory jurisdictions, ILSI Europe has taken an initiative to establish clear criteria and a framework to determine the public health importance of a given food allergen. These criteria will consist of factors relating to food properties, population factors, and exposure factors.     

从过敏原危害评估食物过敏风险

随着全球食物过敏发生率的逐年升高,食物过敏性疾病已成为人们日益关注的食品安全和公共卫生问题。本文介绍了食物过敏原特性、致敏机制、临床表现、常见致敏食物及主要暴露来源等内容,概括了食物过敏原阈值及参考剂量的制定方法和最新调整情况,并总结了目前国际上公认的几种食物过敏原的风险评估方法,以期对下一步开展我国人群食物过敏风险评估提供理论依据。     

芝麻过敏原分子特征与检测方法研究进展

食物过敏已成为全世界范围存在的公共健康问题,芝麻是一种常见的食物过敏原,对芝麻过敏原的研究日渐深入。目前,芝麻中已确定的过敏原蛋白有7 种（Ses i 1～Ses i 7）。本文综述了近几年来各国对芝麻过敏原的管理规定、芝麻过敏原蛋白的结构特征、加工过程对其结构及致敏性影响、检测方法等方面的研究进展,以期为采用不同工艺、方法消除或降低芝麻过敏原的致敏性提供理论参考,也为过敏原标签标识的实施提供理论依据。最后,本文总结了芝麻过敏原的研究现状并对未来研究趋势进行了展望。     

Whey allergens: Influence of nonthermal processing treatments and their detection methods

Whey and its components are recognized as value-added ingredients in infant formulas, beverages, sports nutritious foods, and other food products. Whey offers opportunities for the food industrial sector to develop functional foods with potential health benefits due to its unique physiological and functional attributes. Despite all the above importance, the consumption of whey protein (WP) can trigger hypersensitive reactions and is a constant threat for sensitive individuals. Although avoiding such food products is the most successful approach, there is still a chance of incorrect labeling and cross-contamination during food processing. As whey allergens in food products are cross-reactive, the phenomenon of homologous milk proteins of various species may escalate to a more serious problem. In this review, nonthermal processing technologies used to prevent and eliminate WP allergies are presented and discussed in detail. These processing technologies can either enhance or mitigate the impact of potential allergenicity. Therefore, the development of highly precise analytical technologies to detect and quantify the existence of whey allergens is of considerable importance. The present review is an attempt to cover all the updated approaches used for the detection of whey allergens in processed food products. Immunological and DNA-based assays are generally used for detecting allergenic proteins in processed food products. In addition, mass spectrometry is also employed as a preliminary technique for detection. We also highlighted the latest improvements in allergen detection toward biosensing strategies particularly immunosensors and aptasensors.